Do springs and shocks need to be matched to perform properly?

[jjvw]

I'm confused? Are y'all agreeing that springs are springs? Are the Rough Country springs that the previous owner installed as good as Currie's. My RC springs give me 4" lift just like Currie's.

Free length begins to matters when the shocks allow the coils to flop around. The free length matters a lot when you are moving shock mounts around and you want to better match the shock travels to the spring travels.

This thread https://wranglertjforum.com/threads/who-sells-the-best-springs-for-a-4-inch-lift.19918/ asks the OP if he needs length or load capacity. People talk about how long Currie springs free length. They have to have a lower rate.

Correct.

What is this based on? Do you have data?

I have a spreadsheet. Including all coils, front and rear the lightest is a 130lbs giving ~1" front lift and the heaviest is 250lbs giving ~3.75" rear lift. Neither of those can be compared to each other. Once you can group by actual lift heights, the rates become very similar to each other.

What is the rate of the standard spring?

What is the model number? I never paid close attention to the Light, Med, Heavy names. There are several OME coils from other vehicles that fit the TJ. When I was messing around with OME coils, I based any choices on rate and length.

 

[Gollywomper]

Maybe a shock tuner will chime in. But I would think there are more important factors in tuning shocks than minor change in spring rate. Type of driving/terrain and weights both sprung and unsprung. I dunno.

 

[toximus]

coils to flop around.

To add to this. One reason you don't want the coils to become unseated is because there won't be (much) weight on that tire to provide traction. It might not matter on a test ramp, but it does in the real world.

 

[Brianj5600]

Yeah, the main thing you are wanting to accomplish with your springs is a specific ride height with the longest spring possible, meaning a lighter spring rate relative to other springs that accomplish the same ride height

And several have argued that the difference in rate is so small it is a non issue.

 

[JMT]

And several have argued that the difference in rate is so small it is a non issue.

See post #47

 

[Gollywomper]

And several have argued that the difference in rate is so small it is a non issue.

For ride quality it most likely is. But when choosing a spring for maximum travel a longer lighter spring will allow for longer shocks/travel vs a shorter heavy spring with less extended length.

 

[Fargo]

I think the confusion in all of this is everyone is focusing on ride quality. When people think ride quality, everyone immediately is looking at how soft it rides. Or in other words the compression of the shock/spring combo. I completely agree that when it comes to compression, the spring rate is practically irrelevant. My issue has always been with rebound. I don't think most people notice how quickly or slowly their Jeeps respond in the reboud phase of the cycle. But that is where I am arguing the spring and shock need to be tuned to work together.

 

[jjvw]

And several have argued that the difference in rate is so small it is a non issue.

Look at what some of us are doing with outboarded rear shocks. Compared to other 4" options, Currie 4" coils have a short bind height and long free length that pairs nicely with a 12"+ travel shock.

 

[jjvw]

I think the confusion in all of this is everyone is focusing on ride quality. When people think ride quality, everyone immediately is looking at how soft it rides. Or in other words the compression of the shock/spring combo. I completely agree that when it comes to compression, the spring rate is practically irrelevant. My issue has always been with rebound. I don't think most people notice how quickly or slowly their Jeeps respond in the reboud phase of the cycle. But that is where I am arguing the spring and shock need to be tuned to work together.

I can understand the thought. Unfortunately, rebound is yet another variable to chase and find a balance with un-tunable, off the shelf parts. Maybe you will find a spring/shock with the desirable rebound characteristics, but how well do the other considerations play out? The practical reality is that you will always be stuck with one or more compromises until you can get to a place where you can separately tune the individual variables. Even then, Blaine is suggesting that the shock valving is the most significant area of adjustability once the ride heights and travels are established.

 

[Gollywomper]

I think the confusion in all of this is everyone is focusing on ride quality. When people think ride quality, everyone immediately is looking at how soft it rides. Or in other words the compression of the shock/spring combo. I completely agree that when it comes to compression, the spring rate is practically irrelevant. My issue has always been with rebound. I don't think most people notice how quickly or slowly their Jeeps respond in the reboud phase of the cycle. But that is where I am arguing the spring and shock need to be tuned to work together.

For the sake of this thread. Matching a spring with an off the shelf shock may be impossible. Closest option would be getting shocks from the spring manufacturer. But I bet vehicle weight and unsprung weight would play a very big role in this as well, as that changes rebound rate significantly.

 

[Brianj5600]

For ride quality it most likely is. But when choosing a spring for maximum travel a longer lighter spring will allow for longer shocks/travel vs a shorter heavy spring with less extended length.

I guess what makes me question this, is that there is very little data on spring rates, yet it is dismissed as a non issue in comfort. jjvw's Jeep has soft enough spring/shock package that he can use all his up travel driving around town, and he has more than most. I doubt I used half of mine around town even with old worn out shocks that came on it.

 

[jjvw]

... Closest option would be getting shocks from the spring manufacturer. ...

For fun, lets focus on Rancho shocks and coils. They offer one set of coils for a certain advertised ride height. But we can select the 5000, 5000x, 7000, 9000, etc. Each of these shock series is different than the other. Which series was designed with their coils in mind?

 

[jjvw]

I guess what makes me question this, is that there is very little data on spring rates, yet it is dismissed as a non issue in comfort. jjvw's Jeep has soft enough spring/shock package that he can use all his up travel driving around town, and he has more than most. I doubt I used half of mine around town even with old worn out shocks that came on it.

Most of the travel going to the grocery store. Some may say that the valving on my fancy used shocks is wrong for my setup.

 

[Fargo]

For fun, lets focus on Rancho shocks and coils. They offer one set of coils for a certain advertised ride height. But we can select the 5000, 5000x, 7000, 9000, etc. Each of these shock series is different than the other. Which series was designed with their coils in mind?

My first question would be are all the the shocks tuned exactly the same or do they tune the shocks differently for different lengths and expected loads. Or does one shock tune fit all applications.

 

[jjvw]

My first question would be are all the the shocks tuned exactly the same or do they tune the shocks differently for different lengths and expected loads. Or does one shock tune fit all applications.

Just a hunch, I don't think we pay enough for a Rancho or Bilstein for them to change the valving to match the various travel lengths within a series. I could be wrong in that assumption.

 

[Gollywomper]

For fun, lets focus on Rancho shocks and coils. They offer one set of coils for a certain advertised ride height. But we can select the 5000, 5000x, 7000, 9000, etc. Each of these shock series is different than the other. Which series was designed with their coils in mind?

A phone call may answer that. I was thinking about OME on how they say the shocks were matched to their springs. But even there they have one shock for a lift height regardless of spring rate?

 

[Brianj5600]

I think the Wrangler crowd is a bit behind in DIY stuff. We are too willing to accept what is available. My next shocks will be serviceable and I will make adjustments to them. I re-valved my MX and road race motorcycles and not afraid to take on changing my own stacks. The Tacoma community seems to have pretty good support on valving and I may infiltrate them for help.

Fargo, if you want to get the ride you want it will likely be custom. In the 80s anyone that could seriously tune shocks, racing carburetors etc did not share any info. Shocks are not rocket science and with the internet they are no longer black magic.

 

[jjvw]

Yeah, I win... Seriously though, did I miss it? I'm really trying to learn something here and not just argue.

I don't understand how the rate of the spring doesn't affect the valving of the shock. In your coil over example, can you change out the springs with stiffer or softer springs that give you the same ride height and not have to retune the shock. Surely the shock doesn't work with any springs that produce the same ride height regardless of weight. What am I missing?

I want to go out on a limb and add to this.

On some level, the spring rate absolutely factors into the shock tune. As does any inherent bind and damping within the suspension, sway bar resistances, weight, etc. That is a reason why the shock tune is one of the last things to work though. The final valving factors in all these characteristics. If a characteristic is changed then that might affect the tune.

 

[Gollywomper]

I think the Wrangler crowd is a bit behind in DIY stuff. We are too willing to accept what is available. My next shocks will be serviceable and I will make adjustments to them. I re-valved my MX and road race motorcycles and not afraid to take on changing my own stacks. The Tacoma community seems to have pretty good support on valving and I may infiltrate them for help.

Fargo, if you want to get the ride you want it will likely be custom. In the 80s anyone that could seriously tune shocks, racing carburetors etc did not share any info. Shocks are not rocket science and with the internet they are no longer black magic.

I agree that the best ride will come from a custom tuned shock. As far as DIY on tuning. I don’t expect to “play” much with tuning. With The cost of tools to properly assemble and charge shocks just not sure I would pencil out vs having them done by an experienced tuner. For the average daily/trail rig I would think a professional would get the tune close. Even then changes can be made relatively cheap.

 

[jjvw]

I think the Wrangler crowd is a bit behind in DIY stuff. We are too willing to accept what is available. My next shocks will be serviceable and I will make adjustments to them. I re-valved my MX and road race motorcycles and not afraid to take on changing my own stacks. The Tacoma community seems to have pretty good support on valving and I may infiltrate them for help.

....

My dad is getting back into the Jeep world after about 15 years away. These types of discussions weren't happening in his circles in the '80s-'90s. The idea that shocks might matter on a Jeep was a new concept when we started comparing his old with my newer.